Substituted polythiophene polymers have received extensive attention in recent years due to their nonlinear optical properties, electro-conductivity and many other valuable properties. They can be used in a number of applications including electronic and optical devices, such as field-effect transistors, sensors, light-emitting diodes (LEDs), rechargeable batteries, smart cards, and non-linear optical materials. The use of these polymers for such applications has been hampered by some of the properties of these polymers, but most importantly their methods of synthesis. Conventional methods of synthesis do not create pure polymers with respect to regiospecificity, which has been recognized as playing an important, if not critical role, in determining the physical properties of conducting polymers.
U.S. Pat. No. 5,756,653 describes the first known method of providing regiospecific (regioregular) polythiophene polymers. This method employs highly reactive zinc species as precursors to the polymers which are costly and hard to handle. Furthermore, the polymerization reaction may take up to 5 days to complete.
U.S. Pat. No. 6,166,172 describes a method of forming regioregular poly-(3-substituted)thiophenes by combining a soluble thiophene having at least two leaving groups with an organomagnesium reagent at reflux temperature to form a regiochemical isomer intermediate and adding an effective amount of Ni(II) catalyst to initiate a polymerization reaction at reflux temperatures. The reaction is said to yield major amounts of regioregular polythiophene.
Thus, there still remains a need for better synthetic methods for manufacturing substituted polythiophene polymers having high amounts of regioregular polymer. Also needed are devices with high purity regioregular polythiophene polymer components for improved ease of manufacture and device operation.